National Concrete Pavement Technology Center

Project description

It is common practice to use supplementary cementitious materials (SCMs) in the production of concrete. The use of SCMs as a partial replacement for cement results in more durable, higher performing concrete, lower energy consumption, and reduced green gas emissions. The most common SCMs are industrial byproducts such as fly ash, ground granulated blast-furnace slag (slag cement), and silica fume. There are also some natural pozzolans being used in the concrete industry such as calcined shale, calcined clay, and metakaolin. There are many beneficial effects of using SCMs for both fresh and hardened concretes, including enhanced workability, reduction in bleeding, reduction in the heat of hydration, strength gain with time, and reduced permeability and improved resistance to chemical distress. The level of improvement achieved differs among the SCMs. Although fly ash is the most commonly used SCM, others are also being used due to a shortage of fly ash. The objective of this synthesis is to document state department of transportation (DOT) practices for using SCMs in concrete.